10 years ago today, I bought an engine in a PU truck, for my boat.

TomY

Alden Forum Moderator
Jun 22, 2004
2,758
Alden 38' Challenger yawl Rockport Harbor
The diesel engine, an Nissan SD-22 was in a 1983 Nissan 720 PU.

My boat had a Chrysler Nissan CN4-33 diesel installed in 1974, to replace the original Graymarine gasoline engine. The CN4-33 was simply a 'marinized' version of the Nissan SD-22 diesel engine. The original SD-22 was introduced in the 60's as an industrial diesel engine designed for water pumps and generators and was used widely around the globe in agricultural applications. The engine was also used in forklifts.

The 1974 CN4-33 ran alright but had always smoked heavily since I owned the boat. Injector work didn't solve the smoke, and it was becoming harder to start(the reason for the problems would reveal itself, later). I looked into rebuilding but finding someone to do it wasn't easy and the idea seemed sketchy.

I looked into new engines. The high cost of the engine was only the beginning. The process to fit a new power plant in the boat, though inviting for many reasons, was more $ than I was willing to spend.

I looked for a used SD and asked around. There were 2 candidates, in my neighborhood! For $1,000. I chose one that came with what sounded like a cliche' engine story.

The sellers story: "I serviced this older woman's Nissan 720 from new until the body rotted away. She only drove it from Cushing to Rockland, once a week (or something). I(he) bought the hulk 720 for the engine, knowing the service and miles (about 70K), with the idea I (he, a Nissan mechanic), would put the engine into something. "

10 years later, he decided to sell it to me.

We wrestled it into my PU truck, I drove home, and I hung it in my shop. I don't consider myself much of a mechanic, but how hard could this be?
83 SD 22 as delivered._.jpg

After pulling the old boat engine I began pulling the marine components: water cooled exhaust manifold, raw water pump and plumbing, etc. I'd soon find out in the newer PU, Nissan bumped up the horsepower by using a different governor to increase the RPM's. That also meant I'd have to swap the Bosch fuel injection pump with the manual governor onto the new engine. After removing all the PU junk from the new engine, and painting the block, I hung the old beast for butchering:
Cn4-33 beauty and the beast2.jpg

Research, gaskets, slowly the new engine went back in time to a lower RPM and horsepower, industrial-marine diesel engine, with few hours.
SD 22 marinized, back to the past._.jpg

Installation day at 7:01 am. My friend Nate would arrive any minute with the travel lift. He on the controls of the crane, and me in the boat; we'd reverse the process of removing the old engine.
Engine install day.jpg

Nate was gone in less than an hour. By 10:55 the engine was on the mounts. I shuddered to think what a process a whole new engine would have entailed.
Engine install day 10-55am.jpg

The engine, knock on wood, is running like a top, 10 years later.

Back to the old engine. What was wrong with it? I'd soon find out. With the hulk in the back of my truck, headed to the metal dumpster at the dump, I decided to do a little dissection.

There was always an odd play, slop, when you rotated the crankshaft pulley, by hand. The crankshaft nut came off with a large ratchet (it should not have, I was told later). I slid the timing gear for the fuel injection pump off the shaft, and there it was.
SD timing gear slid off shaft.jpg

A closer look showed the woodruff key was distorted and worn oddly. No wonder it smoked. Fine engine compression, but the injection pump couldn't be timed.
SD timing gear woodruff key wear.jpg

This was beyond me so I sought out expert opinions. One Britt fella that was educated in marine engineering of this sort of stuff asked me, "Was an extra pulley added to the crankshaft for a large second alternator?"

In fact, there had been. The previous owner had added a 3 belt wheel to the end of the crankshaft for large frame alternator with an oversized belt. I removed that large alternator and installed a dual output Balmar, years before.

He went on to list engines he'd worked on, that had been damaged by a lack of engineering in adding pulleys. He couldn't say for sure that was the reason but the timing gear should have never moved. Perhaps in the install of that extra alternator, the mechanics didn't torque the triple pulley on sufficiently. Or the sheer side loaded of that extra belt, loosened things.

Either way, that engine was indeed, toast. During a rebuild, it would have required a new crankshaft.
 
Jul 23, 2009
857
Beneteau 31 Oceanis Grand Lake, Oklahoma
Nice wright up and pix.
Good find too.
I'm sure the crankshaft could have a new key-way cut into it and use a longer key. The timing gear would likely need some work too.
 
  • Like
Likes: TomY